Variable condenser



Wimmh 11H, l fi). DUEHJER 1,75%393 VARIABLE CONDENSER Filed May 12, 1925 5 Sheets-Sheet l INVENTOR WILL/4M DUB/LE2- ATTORNEYS arch N, 1930 I W. DUBHLIER EJ569393 VARIABLE CONDENSER Filed May 12, 1925 5 Sheets-Sheet 2 INVENTOR WILL/AM DUB/U68 BY @MM ATTORNEYS March 11, 1930. w DUBlLlER 1,750,393

VARIABLE CONDENSER Filed May 12, 1925 5 Sheets-Sheet 3 INVENTOR mun/v DUfi/L/LQ ATTORNEY VARIABLE CONDENSER Filed May 12, 1925 5 Sheets-Sheet 4 I 27 5 I 304 M INVENTQR W/LL/A/W ua/U52 fla Mk Ju /24 ATTORNEYS which 111, 1930 DUBlLlER L75@,3593

VARIABLE CONDENSER Filed May 12, 1925 5 Sheds-Sheet 5 rum v INVENTOR WILL/AM DUB/L/BQ ATTORNEYS Patented Mar. 11, 1930 meat WILLIAM DUBILIER, OF NEW YORK, N.

CORPORATION, OF NEW YORK, N. Y., A

Y., ASSIGNOR TO DUBILIER CONDENSER CORPORATION OF DELAWARE VARIABLE CONDENSER Application filed May 12,

This invention relates to an improved electrical condenser; especially a condenser designed for convenient variation of electrostatic capacity.

The general object of the invention is to provide a variable condenser which can be cuits, althoughit is cheaply manufactured in large quantities; which comprises few'parts that can be easil and quickly assembled; which can operate e ficiently and accurately; and which is capable of giving long service without derangement of either structure or function.

In practice, the condenser according to this invention is very simple in form and is intended for use in connection with radio ciralso adapted for other purposes as well.

The nature and scope of the invention will appear fully from the following description taken with the accompanying drawing which present several forms in which my invention can be embodied; but this disclosure is illustrative only and I may vary the shape, size and relative arrangement of the parts constituting the condenser and-still keep within the principle which controls my invention; and the claims appended hereto are to be con-, strued accordingly in view of the broad terms in which same are expressed.

On the drawings: Figure 1 is an end view of one form of condenser according to my invention;

Figure 2 is a bottom plan thereof shown as if the observer were looking up underneath the condenser appearing in Figure 1, partly in section;

Figure 3 is a side view seen from the right of Figure 1, of said condenser;

Figure 1 is an end view of another form of condenser according to my invention;

Figure 5 is a bottom plan of the condenser shown in Figure 4, partly in section;

Figure 6 is a View of the opposite end of the condenser of Figures 4: and 5, presented as if viewed from the bottom of Figure 5;

Figure 7 shows a detail of the construction of this second form of my improved condenser;

Figure 8 is an end view of a third form of condenser according to my invention,-

1925. 'Serial no 29,733.

Figure 9 is a bottom view of the condenser own in Figure 8, partly in section;

' Figure 10 is a of a fourth form of my improved condenser;

F igure 11 is an end view of a fifth form of a condenser according to my invention, somewhat similar to Figure 8;

Figure 12 is-a bottom View of the condense of Figure 11;

Figures 13 and 14: are plan views, partly in section, of additional modifications of my improved condenser; and

Figures 15 and 16 are respectively, a plan and an end or side view of a still further modification of my "improvedcondenser.

The same numerals identify the same parts throughout.

Referring first to Figures 1, 2 and 3, I use the numeral 1 to indicate a fixed electrostatic member or stator comprisin a curved or semi-cylindrical plate 1, and the numeral 2 to indicate a movable electrostatic member or rotor comprising a similar curved plate;.

plan vlew partly in section these two plates being parallel to each other.

The stator also includes a number of parallel electrostatic elements, in the form of cylindrically curved ridges, ribs or projections 3, separated by intervening deep grooves or re-. 5 cesses 4; and the rotor" further comprises similar cylindrical projections, 5 separated by intervening grooves 6. When the condenser is assembled, the semi-cylindrical projections 5 of the rotor will enter the recesses 4 of the stator, and the projections 3 ofthe stator will enter the recesses 6 of the rotor, as plainly appears in Figure 2; but the projeetions 3 and 5 will no where make elecztrical contact with each other. lVhen seen in end elevation, the rotor and stator will each appear like a comb with teeth, as indicated in Figure 2.

, To hold the rotor and stator in the desired relation, the curved plate or base'carrying the elements 3, is provided with radial .the end of the projection is a rigid arm. 16, held in place by fastening devices or screws 9, this arm extending laterally over concentric circular edges to make the rotor and stat.or,- to some extent, open in the middle, and the insulation 8 is provided with a post 15 which extends through the rotor and stator within the compass of the elements 3 and 5 and adjacent the shaft 11. Fixed to the end 12 of the shaft 11 and carrying a pointed screw 17 which enters the extremity of the reduced portion 12 of the shaft, to

support said extremity and to prevent axial movement of the shaft 11 with the stator 1.

The hub13 can be made rigid with the shaft 11 on the portion 12 in any feasible manner, and when the screw 17 is adjusted, the shaft 11 is forced to bring the end of the hub 13 in contact with the bearing 10. Then the elements 5 will enter the grooves 6 between the elements 3 and yet be out of contact with the stator 1 at all points. On the pointed u screw 17 is a lock nut 18to hold the screw in said position.

The projecting elements 4 and 5 extend at right angles to the arc-shaped plates of the stator 1 and rotor 2, and they may be molded or cast into these plates, or the plates may be cut to provide slots to receive them. As

already mentioned, these elements3'and 5 are semi-cylindrical, that is to say, they are all curved on the arcs of concentric circles which have the axis of the shaft 11 as a center, and each maybe 180 degrees more or less in an 'ular extent. The insulation 8 may be bakeite, and is ofi'set or spaced axially along the shaft 11 from therotor and statorto some extent, in orderto reduce the losses in the operation ofthe condenser. From'the insulation 8 extends two bosses 19 having screw holes 20,, to enable the condenser to be mounted upon a suitable support or panel.

In Figures 4, 5 and 6, the stator is indicatedat 1 and the rotor at 2. Each is provided with substantially semi-cylindrical projections 3 and 5 as before, with intervening grooves orrecesses 4 and 6, and the flat or plane part of the rotor and stator which are normal to the axis of the shaft, instead of being arc-shaped plates, are here given the form of semi-circular discs. From the center of the stator projects a hub or boss to provide a bearing 10 to receive the shaft 11'. This shaft 11' has a peripheral groove 21 adjacent the outside surface of the stator, and in this groove is disposed a locking ring 22. The purpose of this locking ring is to engage a flat slightly concave spring disc 23, having radial cuts or recesses 24. This disc is perforated in the middle to he slipped upon the shaft against the flat outer face of the stator before the locking ring 21 is put into the groove 22, and this ring compresses the springdisc against the stator, for a purpose which isstated below. The stator carries a projection 25 having a threaded opening to receive a binding screw 9 to enable a conductor to be attached thereto.

The portion of the rotor 2 which is normal to the shaft 11 is dished somewhat as shown at 26 and has a central member 27 from the inner surface of which project in a radial direction, a flange or collar 28 'at the inner edge of which are projections 29 adapted to serve as rivets. These portions 29 extend in the same direction as the axis of the rotor 2, and they act to hold in place two discs of insulation 30 and 31. The projections 29 may be in any number, and they extend in both directions axially of the condenser. Preferably, they are arranged in-pa-irs, one of each pair extending towards the stator and the other in the opposite direction. The discs 30 and 31 are perforated near the circumference to enable the ends of the portions 29 to, be passed through them, and the ends of these portions when expanded by pressure, will secure these discs in the manner of rivets to the rotor 2'. When secured, the discs 30 and 31 will have the collar 28 between them as indicated in Figure 5. These discs have central openings to receive a hub or sleeve 32 having a collar 33 31, and a small ring or washer 35 is placed against the face of the outer disc 31,'t-he outer end of the hub 32 passing through this ring 35 and being expanded by pressure, to hold the hub 32 on same. In practice,'the rotor 2 is assembled with the discs 30 and 31, and the sleeve 32, and the ends of the rivets 29 and of the sleeve 32 are expanded to secure the hub 32, the discs 30 and 31, and the stator together. Then the rotor 2 can easily be mounted upon the shaft 11 by slipping the hub over the endof the shaft 11 until it abuts a shoulder 36 which will be at the inner end of the bearing 10'. The outer extremity of the shaft 11 will then be expanded the same as the adjacent'end of the sleeve 32 and thus the rotor 2 and the shaft 11- will be secured together. The location of the locking ring 21 will be such that while it keeps the spring disc 23 pressed against the fiat part of the stator 1', this spring will so act upon the shaft 11 as to move it axially as far as the end flange or col-t lar 33 on the sleeve 32 will permit. That is to which it carries, in correct relation to the I stator 1, that is, with the elements 5 the greases proper distance at all ments 3.

The rotor 2' is provided with a flange 37 that is milled along the edge thereof, and affixed to the straight edge of the portion of the stator 1 which is perpendicular to the stator 1', is a piece of insulation 38 on which is fastened a contact strip 39. From this contact strip runs a piece of insulated wire 40 to one of the rivets 29 to make connection to the stator 1. V

I The stator 1 also carries a Vernier adjusting device comprising a rotatable stem 41 which extends through-bearing apertures in radial projections 42. This stem has a shoulder 43 whichis flush with the lower points from ,the eleface of the upperprojection 42 in Figure 5,

and between the projections, and encircling the stem 41, so as to engagethe shoulder 43, is a coil compression spring 44. Beyond the other projection 42, the stem 41 carries a fibre friction wheel '45 which fits against the shoulder 46 near the extremity of the stem, and is held in place by riveting over the extremity of the stem 41, as indicated at 47. Both the wheel and the milled flange 37 are coned to a slight extent, and the spring 44 acts to keep the stem 41 retracted, and the wheel 45 out of engagement with the rotor 2. lVhen one wishes to use this Vernier attachment, he pushes the stem 41 to bring the wheel 45 against the flange 37, and then turns the stem 41 to give the, minute adj ustment, of the rotor desired. v

In both forms of condenser thus far described, it is seen that the adjustment is made by turningthe shaft carrying the rotor, so as to cause a larger or smaller portion of the outside surfaces of the elements or armature's 3 and '5 to be in juxtaposition with each other. Both the rotor and the stator have ,portions which are perpendicular to the operating shafts, to serve as a base on which the elements 3.and 5-are'mounted. The elements 3 and 5 do not have their opposite faces parallel, but they are rather tapered. That is to say, the oppo-c site faces of each substantially semi-cylindricalelement 3 or 5 converge towards theouter edges of these elements; and this construction is made so that when the stator and rotor are case, they cannot only be withdrawn; easily, from the molds; but also theycombine the greatest possible strength with the greatest possible thinness, and not only is material saved, but bending of the plates out of proper position is prevented.

In the form shown in Figures 1, 2 and 3,

the stator is insulated from the shaft, and the rotor and shaft are electrically connected. The range of adjustment is about 180degrees,

and the post 15 will act as a stop for the rotor in the position of both maximum and mini- 1 mum capacity.

In the forni of condenser shown in Figures 4, 5 and 6, the piece of insulation 38 acts as a stop for the rotor in the position of both maximum and minimum capacity, and the range of rotation is'about one-half circle, as before. In this type of condenser, the stator and the shaft-11 are in electrical connection, so that they can be of the same potential; while the rotor is insulated from the shaft and the amount of insulation is actually very small. The amount of taper which is given to the armatures 3 and 5 will be 7 more than one degree.

In these two forms of condensers, it is desirable that the elements 3 and 5 be secured to the plates or portions normal to the operating shaft of the rotor and stator, because so these plates or portions serve as bases or heads, and the armatures 3 and 5 with these heads or bases can either be cast in one piece, or the armatures can be rolled or punched,

and afterwardsattached to these heads or bases at right angles to the surface thereof, and in proper position with respect to the axis of the operating shaft.

In the form of my condenser shown in Figures 8 and 9, the stator l comprises radiating arms 7 that are preferably of metal made fast to a head of insulation 8 by means of screws 9, washers 48 being interposed between these arms 7 and the insulation .8. The arms 7 on one side are slotted to receive semi-cylindrical elements or armatures 3 the edges ofwhich cut into the slots and these elements maybe made fast by being cast with the arms 7, or otherwise. The ro tor 2 is preferably in the form of a semicircular disc bearing substantially semi-cylindrical armatures or elements 5 which enter spaces between the elements 3. From the center of the semi-circular head or plate of the rotor 2 projects a journal or shaft 49 which may be cast in one piece with the rotor or-otherwise secured thereto, and thisshaft has a sloping or conical shoulder 50 to receive a bushing 51, with a counterbored end to fit the shoulder 50. The opposite end ofthis bushing is also counterbored to re ceive a washer 52 having a coned face, and on this washer is a perforated spring disc 53. Adjacent the washer 52, the shaft is threaded to receive a couple of lock nuts 54.which press down upon the spring disc 53. lVhen these look nuts are turned up, they hold the sleeve or hearing 51 snugly between the wa sher.52\and the shoulder 50, and as this sleeve 51 is made fast inside of a hubor boss 10 of the insulation 8'. the heads of the rotor and stator are held the required distance apart.

In Figure 10, the stator 1, the rotor 2 and 9 the armatures 3 and 5'with the 'grooves 4- and'6, are shaped substantially the same as in the case of the condenser shown in Figures 1, 2 and 3; except that, the stator has no ribs 7, but is made fast to the insulating head 8 by fastening deVicesfQ and washers 48, the

same as in the condenser shown in Figures 8 and 9. Figure 10 shows the rotor having the shaft 11 projecting from the middle of same and otherwise the construction and manner of mounting-the shaft 11" to turn withthe stator in the insulation 8, is the same as in Figures 8 and 9.

In Figures 4 to 10 inclusive, the bosses 19 with screw threaded holes 20 are also shown for mounting the condensers on a panel.

In Figures 11 and 12, the form there shown comprises a stator 1 which includes a substantially semi-circular plate of conductive material bearing substantially semi-cylin drical elements or armatures 3; The rotor 2 likewise embraces a substantially semicircularplate orhead from the face of which projects substantially semi-cylindrical ele ments or armatures 5, the armatures of each set projecting into the spaces of the other set. From the inner face of the head of the stator, projects a bearing 10 in which is mounted the shaft 11. This shaft like the condenser of Figure 5 has a groove 21 with a locking ring 22, and a spring disc 23 on the shaft abutting the ring 22, and the stator 1 In the head of the rotor is a bearing 27 which is filled with insulation 30 molded or otherwise secured in this bearing and carrying in its middle, a sleeve or hub 32' which -is slipped upon the end of the shaft 11 as a journal,-and has a collar 33 at one end, while over the shaft is passed a washer 35 held in place by a lock nut 55 and pressed against the insulation 30*, and the opposite end of the sleeve 32. Normally, the sleeve 32 will abut both the bearing 10 and a shoulder 36 on the shaft 11.

In this form of condenser as that shown in Figures 4, 5 and 6, the elements 3 and 5 may either be cast in the heads of the rotor and stator, or they may be rolled or punched and inserted into slots cut in the opposing facesof the rotor and stator.

Figure 13 shows a further modification in which the stator 1 is in two parts, each comprising a head or plate from the one face of which projects elements 3, the opposite faces of which converge as in Figures 2, 5 and 10, the elements 3 being separated by grooves or recesses 4, and the two heads are connected by a cylindrical casing 56, held to the rims of the two heads by screws 9. The rotor is disposed inside of the casing and it comprises a head or plate with armatures or elements 5 on both faces, separated by groovesfor recesses 6. The elements 5 on both faces of the rotor which are located at the same radial distance from the axis of rotation, are in line with each other, so that the elements 5 all.

can project into the spaces 4 of the stator. One of the stator heads has a central bearing 10 in which is a bushing or jacket 57, receiving a shaft 11", the outer end of the, jacket being flanged at 58, and the inner end being threaded at 59 to receive a nut 60.\ The head of the rotor has a central bearing opening 27 in which is secured insulation, the same as described in connection with Figuresll and 12, and at the middle of the insulation is a hub or sleeve 35 having a flange or collar 33,

at one end, and encircled at the other end, by a washer"35 secured against the face of the insulation 30 by riveting over or expanding the adjacent end of the hub 32. This hub is slipped on the reduced end of the shaft 11", and abuts a shoulder 36 adjacent the inner end of the shaft 11 and adjacent the inner end of the bushing-57. The other stator head has a threaded opening to receive an adjustable pointed screw 17 carrying a lock nut 18, the point of this screw engaging the inner end of the shaft 11 both to support the inner end and to hold it in proper axial position. Obviously, if the hub 32' is made fast on the reduced extremity of the shaft 11 in front of the shoulder 36, and if the.

armatures 5, andthe elements 3 of the other stator head carrying the screw 17.

Figure 14 shows a variablecondenser with a twopart stator 1, each stator head'having armatures 3 separated by recesses 4, and the rotor 2 carries armatures 5, separated by recesses 6, which are staggered on the two sides of the rotor; that is, the armatures on one side of the rotor are not in alinement each to each with the armatures on the other side, and the armatures 3 of the stator are correspondingly arranged. The two'heads of the stator may be mounted in any suitable manner in fixed position by means of projections 19, as shown in the other views, or otherwise. At the centers of the two parts of the stator are inset pieces of insulation 30", one of which carries a pointed regulating screw 17 with a lock nut 18 to engage the inner end of the shaft 11'. The stator is fixed to the shaft, and has a central hub 61 disposed against a shoulder 36 of the shaft 11. The other stator carries-in the middle of the insulation 30, a bearing 57 having a flange 58 and carrying on its opposite end a nut 59, this bearing being rigid in the stator head carrying it, and the shaft 11' passing through this bearing. In this condenser, I

that is, if radial lines P menses section are separated by fiat sector-shapedspaces on the head of the stator as indicated in Figure 15. Hence, the separate groups of armatures 3 are really sector shaped also, were drawn from the center of the stator along the ends of the armatures of each group, a sector of a circle would be enclosed. Hence, the armatures are not substantially semi-cylindrical, although they are cylindrically curved; but, are less than a semi-cylinder in circumference. The rotor 2' comprises a plate or head of insulation perforated at the middle and carrying a hub or sleeve 32 having a collar 33 engaging one face of the stator, so that the stator can be mounted on the reduced end of the shaft 11 and abut a shoulder 36. The

stator is retained on the shaft by a washer 35 and anut 55. This rotor. comprises armatures 5, separated by recesses 6 in three groups arranged as described in connection with the stator; and the armatures of each group for the rotor may be formed by casting, machining, or otherwise, as separate units, each consisting of a plate or head 62 from one face of which the armatures pro-- ject, the heads being securedto the head of the rotor 2 by screws 9. The head of the stator can be mounted on a panel infixed position by means of projections 19 having screw holes 20, as employed above in conneca 12 and 13; between the bushing 51 and the tion with all the other views.

. 'When the condenser of Figures 15 and 16 is adjusted so that the armatures of the rotor will lie in the sector-shaped spaces between the endsof the armatures of the stator, the capacity will be a minimum, and when. the rotor is turned to move its armatures into the spaces 4, so that the ends of the armatures of each group of the rotor coincide with the ends of the armatures of each group on the stator, the capacity will be a maximum.

Referring again to Figure 5, the stator is shown as provided with a projection 10" from the bearing 10, to give added support to the piece of insulation 38.

For purposes of adjustment, the range of the capacity of the various forms of condensers shown herein can be regulated by the use of shims, which can be placed, for example, between the bushing 10 and the hub 13 in Figure 1, to determine the spaces between the armatures 3 and 5. Such shims can also be used at the ends of the bearing 10 in Figure 5; in the same position between the bearings 10 and the sleeves 32' in Figures conical shoulder 50 in Figures 9 and 10; between the hub 61 and the bearing 58 in Figure 1%; and between the head of the rotor 2 and the head 62 of each unitary group of armatures 5 in Figure 16. Such shims are, in fact, shown at 63, and the number can be varied as desired. Such shims are also shown at 63,between the hub 32 and bearing 10 in Figure 16.

Having described my invention, what I believe to be new and desire to secure and protect by Letters Patent of the United States 1s:

1. A condenser comprising a stator having a head from one face of which semi-cylindrical armatures project, said armatures being separated by recesses, a rotor comprising a similar head from the face of which substantially similar armatures project into the recesses of the armatures on the stator, the stator having a central bearing, a shaft extending through said bearing, the rotor having a central opening with an inside collar, projections extending in opposite directions disposed at points around the inner edge of the collar, discs of insulation on both sides of said'collar receiving said projections, and held in place thereby, a hub having a flange at one end passing through said discs, a washer on said hub between the said discs, and a washer on the other end of said hub and secured by the expanded end of said hub against the face of the adjacent disc, said shaft having a reduced end with a shoulder upon which said hub is secured, a piece of insulation secured on the stator, a contact pieceon saidpiece of insulation, and a flexible insulated conductor connecting the said contact piece to said rotor.

, 2. A condenser comprising a rotor in the form of a metal head having substantially semi-cylindrical armatures projecting from one face, head, and separated by intervening recesses, said head having a central bearing projecting therefrom, a rotor comprising a head having similar armatures projecting from one face thereof, and into the recesses between the armatures of the stator, the middle of said head having a bearing opening, insulation secured in the bearing opening, a central sleeve mounted in said insulation and secured therein to be disposed on the end of the shaft, and engage a shoulder thereon adjacent the end of said bearing, and a-spring disc engaging the shaft to cause said sleeve to abut said bearing.

3. A condenser comprising a fixed member and a movable member, each member having a head with cylindrically curved armatures separated by recesses projecting therefrom, the armatures of one member extending int the recesses of the remaining member, means comprising shims for adjusting extent to which the armatures of one head project into the recesses of the other.

i. A variable condenser comprising a stator, a bearing in the stator,

a shaft in the bearing, a supporting member in said rotor, and insulation in said last named member between the shaft and the secured along their edges, to the a rotor having rotor, said insulation being in the form of discs riveted to said member.

5. A variable condenser comprising a stator, a bearing in the stator; a rotor having a shaft in the bearing, a supporting member in 'said rotor, and insulation in said last named member between the shaft and the rotor, said insulation carrying a central hub for receiving said shaft.

In testimony whereof I afix my signature,

| 1AM DILIER. 

